Refrigerating apparatus



WET BULB F F. R. BICHOWSKY BEFRIGERATING APPARATUS Original Filed 001:. 29, 1932 June 10, 1941.

- 4 Sheets-Sheet 1 DRY 'BULB INVENTOR. BY M a? :00 a0 e0 40 20v 0 M 14/ PERCENT ATTORNEYS.

June 10, 1941. BICHQWSKY' 7 2,245,455

' REFRIGERATING APPARATUS Original Filed Oct. 2 9, 1932 4 Sheets-Sheet 2 INV ENTOR.

ATTORNEYS.

June 10, 1941. F. R. BICHOWSKY 2,245,455 REFRIGERATINGAPPARATUS Original Filed Oct. 29, "1932 4 Sheets-Sheet 3 0E1% BY ATTORNEYS F; R. BICHOWSKY REFRIGERATING APPARATUS June 10, 1941.

Original Filed Oct. 39, 1932 4 Sheets-$119914 INVENTOR.

ATTORNEYS Patented June 10, 1941 BEFRIGERATING APPARATUS Francis R. Bichowsky, Ann Arbor, Micln, assignor to General Motors Corporation, Dayton, Ohio, a. corporation of Delaware Original application October 29, 1932, Serial No.

640,228. Divided and this application January '7, 1938, Serial No- 183,8'l5

2Claims.

This invention relates to refrigeration, heating and air conditioning.

This application is a division of my copending application Serial No. 640,228, filed October 29, 1932, now Patent No. 2,212,852, dated Aug. 27, 1940.

It is among the objects of this invention to provide refrigerating, heating and air conditionlng apparatus capable of maintaining the desired effective temperatures in dwellings, theatres and other places occupied by human beings, the op: eration of these apparatus being automatic inso far as controls are used for controlling part or all of the functions of the apparatus to'maintain the. air at the desired effective temperature.

Further objects and advantages of the present invention will be apparent from the following. description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings: v

Fig. 1 is'a chart indicating the relationship between dry bulb, wet bulb and. effective temperatures;

Fig. 2 is a plan view, somewhat diagrammatic, of a control adapted to control the functions of air conditioning apparatus in accordance with the effective temperature, and, if desired, also the dry bulb or wet bulb vtemperatures or both;

Fig. 2a is a cross sectional view taken along the line 2a2a of Fig. 2;

Fig. 3 is a diagrammatic showing of an apparatus in which the control is based on the effective temperature and .the'control operates on the air flow functions of the apparatus;

4 is a diagrammatic showing of an apparatus, somewhat similar to Fig. 3, but in which the control is effective on the liquid temperature functions of the apparatus; l

Fig.5 is a diagrammatic showing of an apparatus in which the control is effective both on the air flow and liquid temperature functions of the apparatus, and in which the control device may also be modified in accordance with outside temperatures; I

Fig. 6 is a diagrammatic showing of an apparatus in'which .the control is effective came In air conditioning, as applied for human comfort, the usual methods of controlling the temperature and humidity of the air in dwellings and places of human occupancy, has been. such as to maintain in an enclosure, air of a definite fixed temperature and humidity. Recent investigations on the conditions of air necessary for human comfort, indicate that such a method of controlling is undesirable. It is now well known that thedesirable condition for human comfort in a dwelling, or any other place of" human occupancy, is to maintain the air at an efiective temperature, which varies with the outside temperature.

By an efiective temperature, I mean, as is usual in this art, the combination of state of humidity and temperature as given by the well-known table, such as those published by the American Society of Heating and Ventilating Engineers, it being a characteristic feature of the efiective temperaturm as defined by the relation of temperature and humidity as given in this table, that the effective temperature measures the sensation o-f hotness or coldness, relative to the human body by the average observer.

The relationship between the wet bulb, dry

bulb and effective temperatures will be more fully discussed with reference to Figs. 1 and 2 hereafter.

In general therefore, it is desirable in the control of the temperatures and humidities used in air conditioning, to maintain neither a constant temperature nor a constant humidity but temperature of a cooling surface and on the air temperature.

to maintain the relationship between temperature and humidity, such that the space of occupancy is kept at a-constant efiective temperature.

It has been in the past, impossible to accomplish this in any automatic manner because of the lack of any control apparatus respondent to that combination of conditions of temperature and humidity which constitute efiective temperatures.

In the invention as herein specified, I accomplish the control of the temperature and humidity of the air in such-a way as to maintain the desirable relationship between temperature and humidity, which corresponds to maintaining the air at a constant effective temperature.

In general, the means which I employ to this end are the coupling together of a temperature respondent device and a device respondent to the relative humidity or. to any property of the air which is determined by the relative humidity of the air, either independent of the absolute. temperature of the 'air or as related to the absolute temperature of the air. For example, I may employ in place of a device responsive to the relative humidity; a. device responsive to the wet bulb temperature of the air; a device responsive to the dew point of the air. Various means may be employed under this invention of, say, connecting the two devices-one responsive to the temperature of the air and the other re- I sponsive directly or indirectly to the humidity of the air in such a way that the joined induction of these two devices will indicate the effective temperature of the air.

I am well aware of the fact that the relation-. ship between temperature-and humidity, defining the effective temperature, is not the same at different effective temperatures, but for the purpose of conditioning air for comfort, the desirable region of effective temperature resides around the effective temperatures of about from 65 to 75, and in this region of effective temperature, the relationship-between ltemperature and humidity, for example, as indicated in Fig, 1, is essentially linear and of constant slope. This fact makes it possible, by restricting the application of the device to this region and neighboring regions to so couple .the device that a motion of the temperature sensitive element, taken in conjunction with a motion of an element whose motion is linearly proportional to the relative humidity, may be coupled in such a way as to produce an element, whose motion will be 'proportion-a1 to the elIective temperature. This element being used to actuate a device, whereby directly or indirectly, the condition of the air may be 1 controlled so as to maintain essentially constant efiective temperature of this air. Or under this invention, any device respondent to effective temperature may be used to control the temperature and humidity of the air in such relation that their effective temperature remains constant.

It is, in general, necessary for comfort to maintain the effective temperature at a predetermined value, it is desirable in places in which persons are entering or leaving to vary the efiective temperature desired in accordance with the outside temperature and for that reason it is desirable in any means controlling air conditioning apparatus to provide means of varying the control temperature in accordance with the external temperature as well as the effective temperature.

In the description I will first describe means of maintaining an effective temperature, it being understood that the effective temperature desired will depend also on the outside temperature.

The various means known in the art for conditioning air differ in the manner in which a desirable condition of temperature and humidity are maintained. In the usual means of producing cold and dry air, as employed in the art, it is usual to contactthat air with a cold fluid, which at the same time cools the air and dries it. The relation of temperature and humidity of the air as so conditioned, is fixed by the relation of aqueous tension to temperature of the contacting liquid.

With the apparatus employing this means of conditioning air, it is not most desirable to control the humidity in such a way as to keep a constant humidity or to control temperature in such a way as to keep the constant temperature, but it is desirable to control the temperature or the cooling medium or the concentration of the cool-v ing medium if the mediumis an aqueous solution in such a way that the resultant air will have a controlled effective temperature. I

11 accomplish this by introducing into the air,

whose effective temperature it is desirable to maintain constant, a device such as described above, responsive to effective temperature, the controls on such device actuating a means for controlling either the quantity of the contacting liquid exposed; the quantityof air placed in contact with the liquid, the temperature of the liquid placed in contact with the air, or the concentration of the liquid, if the liquid is a solution.

In other means of conditioning air for comfort, as known in the art, the air is cooled out of contact with a. liquid to such a temperature that a portion of the moisture in the air is precipitated on the cold surface exposed to the air. When this means of air conditioning is employed, it is desirable to maintain the effective temperature at a predetermined value. I do this by putting in contact with the air a device responsive to the effective temperature of the air, such a device actuating a valve or switch or other means controlling either the temperature of the cooled surface incontact with the air, the quantity of air passed over a said surface or the amount of surface exposed to the air.

Another class of devices for conditioning air, known to the art, separate the process of drying the air and cooling the air, so that by changing the devices governing the drying and cooling, it is possible to independently control the humidity of the air or the temperature of the air.

According to my invention, the air may be brought and maintained at a desired effective temperature, either by controlling the temperature of the air or by controlling the humidity, or the relation of the temperature to humidity may be kept at any desirable relation by suitable interconnection between the valves or other devices controlling the amount of drying accomplished and the valves or other devices controlling the temperature of the air.

Having specified my invention in general, I proceed to describe more in detailone embodiment of the invention, it being understood that any other embodiments falling within the scope of the invention may be'used in place of those herein described.

In Fig. 1 the line B is a scale indicating dry bulb temperature, the line A is a scale indicating wet bulb temperature and the line C is a scale indicating effective temperature. In all of these scales, the numerical values are equal vertically,

that is,,all points on these scales which are equally distant vertically from a common horizontal base line have the same numerical values. Thus, if a wet bulb thermometer is placed adjacent the line A and a dry bulb thermometer adjacent the line B of proper calibration so that each thermometer indicates correctly on its corresponding scale, these thermometers would indicate the same numerical temperature only when air has relativehumidity. The line C is so constructed that it intersects the line B at approximately the 42 F. point and intersects the line A at approximately the, 100? F. point, the line C being, for the purpose of this invention, a straight line between these two points. In order to indicate the eflective temperature prevailing at any particular time,.it is only necessary to construct a variable line E starting-from the point P which corresponds to the indicated wet bulb temperature andextending to the point G which corresponds to the indicated dry bulb temperature. The intersection. or the line E with the line-C at the point H gives the eflective temperature prevailing in the atmosphere being investigated. Thus the line E is a variable line which follows the dry bulb temperature at one end and the wet temperature at the other end, and indicates, atits intersection with the line C at the point H the effective temperature.

Fig. 2 shows a device by which it is possible to control the effective temperature of a space either to a constant value or to a value which depends on 53 correspondingto the dry bulb temperatures of line B, Fig. 1. Scale 54 is placed on the device so as to correspond to line C of Fig. 1. The point 55 corresponds to the point occupied by the indicator on shaft 53 when the dry bulb temperature is 42 and the point 55 corresponds to the point occupied by the indicator on shaft 5| when the wet bulb temperature is 100. A lever 51 is freely pivoted on the shafts 5| and 53 to produce a line corresponding to the line E of Fig. 1, so that th controlling edge 55 of the lever 51 indicates on the scale 54 the effec- -tiv temperatures corresponding to the point H of Fig. 1. If desired, upwardly resilient contacts or controls 59 and 55 having sloping ends 59a and 55a are placed on the scale 54 to operate Various air conditioning apparatus in -a manner hereafter more fully described, and these points 59 and 55 may be mounted on carriages 6| adjustably sliding on the scale 54 and held in adjusted position by thumb screws 5 la, so that the carriages 5| may be manually set at any desired point to vary the position of the contacts 59 and 55, or the carriages may be operated by a bellows 62 connected to a thermostatic bulb 63 placed outside of the building, so that the contacts 59 and 55 may be adjusted in accordance with outside temperatures. The contacts 59 and 55 permit the edge 58 to pass over them, but maintain electrical contact as long as the edge 58 is over'them. In addition, other contacts such as 64 and 55 may be placed in the path of movement of the shaft 5|, these contacts controlling portions of the air conditioning apparatus in accordance with-wet bulb temperatures; and other contacts 55 and 51 may be placed in th path of shaft 53 to control portions of air conditioning apparatus in accordancewith dryabulb temperatures. The contacts 54, 55, 55 and 51 are mounted in slots as shown in Fig. 2 so that their position relative to the cooperating contacts may be adjusted.

By virtue of the above described angular relationship of the slides 5| and 53 and the lever 51, a unit change in the wet bulb temperature exerts a greater influence at higher dry bulb temperatures than at lower dry bulb temperatures. Referring to Fig. 2, it will be noted that at high dry bulb temperatures movement of the slide 5| causes the lever 51 to pivot about a point which is further away from the contacts 59 and 55 than at low dry bulb temperatures.

Fig. 3 shows a system for controlling the opertion of an air conditioning system in which the temperature and humidity are jointly controlled by spraying a portion of the circulated air with cold water in th spraying chamber l5. Such systems may be advantageously controlled to give a constant efiective temperature either by controlling the amount of air circulated through the spraying chamber or, as illustrated hereafter, by controlling the temperature of the spray. In Fig. 3 the effective temperature responsive device, described above, which will be for convenience called an etostat 15, is placed in the space to be conditioned I55. Connections are so arranged between the etostat and the fan 25 so that as the effective temperature reaches a value above that indicated by the position of the contact 1|, the flow of the air stream will be increased by starting or increasing the speed of the fan 25 which may supplement another fan, not shown, while if the effective temperature reaches a value below that indicated by the contact 12 the flow of air will be decreased by stopping or slowing up th fan 25. The shutters 35 may be arranged to control the amount of air passing through the chamber |5 or the ratio of air passing through the chamber l5 and the bypass 35. Thus when the contact 1| is closed the shutters are moved by the solenoid 45 ,to increase the flow of air on contact with the dehumidifying or cooling spray 32, and when the contact 12 is closed the shutters 35 are moved to decrease the flow of air in contact with the spray 32. This may be accomplished by a snap acting relay 45 such that when the contact 'II is closed, the lever 4|, under the tension of spring 42 is pulled by the solenoid 43 to close the contacts 44 thus starting the motor 25 and/or causing the solenoid 45 to pull up the rod 45 and open the shutter 35. When the contact 12 isclosed the solenoid 41 pulls the rod 4| to the right thus opening contacts 44, stop ping motor 25 and dropping rod 45 to close shutters 35. The control of the fan 25 may be used with the control, of the shutters 35, or either the fan or shutter control may be used alone.

In Fig. 4, the etostat I55 may be used to control the effective temperature of the space by controlling the temperature or amount of the circulated water sprayed. Thus the amount of water circulated is controlled by turning off or turning on the pump H5, which supplies liquid to the spray I from the sump H2, in accordance with the effective temperature. The temperature of the liquid sprayed may be controlled in accordance with the effective temperature by controlling the cooling means for the water in the sump 2, for example, by turning off or turning on the motor I25 driving the compressor I35 of the refrigerating system |3| which cools the water being circulated to and from the sump H2. The control of either the pump 5 or the motor |25 may be used alone or with the other, so that the amount of water sprayed alone may be regulated, or its temperature alone may be regulated, or both the amount and temperature may be regulated.

It may sometimes be desirable to maintain the humidity below a certain point and at the same time keep the effective temperature constant. By arranging a contact 35| (Fig. 5) in such a position that when the wet bulb, as indicated by the motion of the arm of the lever 352 'nearest the wet bulb 353, reaches a predetermined value, the contact will be made and connecting said contact so that 'as'the wet bulb temperature exceeds a certain amount, the motor driving the refrigerating system will beturned on and as the wet bulb temperature falls below a certain amount, the motor or other driving means allowing the operation of the refrigerating system is turned 011. Thus it is possible to maintain the temperature of the circulating water in the sump 310 and in the spray 3 at such a value that the air entering the enclosure 3I9 is kept at a constant wet bulb temperature. At the same time the efiective temperature may be controlled by connecting the contacts 320 and 32I to the fan 329 or to the shutters 340 as previously described with respect to Fig. 3 so that the fan will be increased in speed or decreased in speed and/or so that the shutters will be opened or closed in accordance with the effective temperature to maintain at the same time. the fiective temperature at a constant selected value or at a value varied in accordance with outside conditions. If the effective temperature is to be varied in accordance with outside conditions, the contacts 320 and 32I may be adjusted along the slideway 322 by the bellows 323 which is connected to the thermostatic bulb 330 outside the building, so that the efiective temperature is maintained at a higher value when the outside temperature rises. If desired, in lieu of the contact 2M, a similar contact may be used at the other side, which contact may be opened and closed in accordance with dry bulb temperatures instead of wet bulb temperatures, the action being similar to that of contacts 66 or 61 of Fig. 2.

In other classes of refrigerating systems, shown diagrammatically in Fig. 6, the air is conditioned by passing over a cooling surface 350. The desirable effective temperature may be maintained by keeping the said cooling surface at the ap-\ propriate'temperature by means of the etostat 310 placed preferably in the space to be conditioned. Conveniently, this may be done by connecting the contact 380 of the etostat in such a way that as the efiective temperature exceeds a predetermined value and the lever 352 makes contact'with the contact 380, an electric circuit is made which will turn on the motor operating the refrigerating system 35] controlling the temperature of the cooling surface 350 which may be the evaporator of the system 35| and so ar-- ranged that when the effective temperature falls below a predetermined value, which value may or may not be a function of the outside temperature as disclosed in Fig. 5, the electric contact between the lever 352 and the contact 380 is broken, thus stopping or slowing down the compressor 352 or other means furnishing refrigeration to the cooling coil 35!]. The effective temperature of the space to be conditioned may be controlled by varying the amount of air passing over the cooling coil in accordance with the response of the etostat. Thus when the contact 380 is closed the fan 315 will be started or have its speed increased and when the contact is broken the fan will stop or slow up. Here also, the controls for the compressor 352 and fan 315 may be used together or either alone.

In Fig. 7, it may be desirable to maintain both a selected relative humidity and a selected effective temperature of the conditioned air, which may be accomplished by providing on the etostat an extra contact 450 so arranged that when the wet bulb temperature exceeds a certain amount the compressor'dM will be turned on and when the wet bulb temperature is below a certain value the compressor may beturned 01!. The efiective temperature may be controlled at the same time in Fig. 6. If desired, in lieu of the contact 450,

by connecting the contact 430 in such a way as a similar contact may be used at the other side, which contact may be opened and closed in accordance with dry bulb temperatures instead of wet bulb temperatures, the action being similar to that of contacts 56 or '61 of Fig. 2.

In other classes of air conditioning systems, the condition of the air is controlled by'the density of a contacting fluid, by the temperature of this fluid, by the amount of air flow and by the temperature of the cooling medium. Systems of this class may be controlled so as to maintain a desired eifective temperature by varying in accordance with the indications of the etostat either the amount of air flowing, the temperature of the cooling medium, the amount of conditioning liquid flowing and the density of the conditioning liquid; or any of these may be controlled jointly so as to maintain a constant predetermined wet bulb temperature and a predetermined effective temperature. 1

Many systems of air conditioning are equally applicable to heating systems alone and to systems which jointly heat and cool. As applied to heating systems, I may either control the temperature of the heating means or the amount of the heating means, this means being either steam, hot air, or hot water, as is usually used in the art; or I can jointly control the effective temperature of the space and at the same time keep the humidity at a predetermined value by so connecting the etostat that as the effective temperature falls below a certain value, the amount of the heating means is increased, while if it falls above a certain value, the amount of the heating means is decreased.

In the case that the air conditioning system is applicable to summer and winter conditions I can arrange the connection to the etostat in such a way thatif the eflective temperature falls below a certain .value, the heating means is turned on and the cooling means turned oif, while if it rises abovea certain value, the cooling means is turned on and the heating means is turned off. v

While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other said enclosure within a predetermined comfort zone comprising means responsive to eifective temperature for controlling said means for effecting said thermal exchange, said effective temperature responsive means including means responsive to changes in the wet bulb temperature for controlling the operation of said compressor operating means so as to limit the effective temperature within said comfort zone.

2. Air conditioning apparatus for an enclosure comprising in combination an evaporator, re-

frigerant liquefying means for supplying liquid refrigerant to said evaporator, means for effecting thermal exchange between a stream 0! air and refrigerant in said evaporator, control mechanism for said apparatus for maintaining the effective temperature in said enclosure within 5 a predetermined comfort zone, said controlmechanism comprising means responsive to one function of the effective temperature of air, means responsive to another function of the FRANCIS-R. BICHOWSKY. 

